I've had a small Brazos HTPC setup on a 46" plasma for a while and have been quite happy with it.

With the advent of a 55" led replacing the ageing CRT in the den I decided I wanted a HTPC there as well so I set out building an i3-3225 on a Z77 board. I use Win 7 (licenced) and XBMC. DXVA is switched on.

Now I'm unhappy with the picture quality. It just seems...too clear. Too much contrast or something. I can't put my finger on it. Best way to describe it is the picture is cold and hard. Cartoonesque, almost.
Watching normal HD TV is fine.

I've been unable to narrow it down. Could it have something to do with refresh rates or something ?

I messed with this for hours and finally decided to put my gt430 back in. The people look like they suffer from rigor mortis and the best I can describe it.

It would be funny but wasting time trying to calibrate the PC to a perfectly calibrated (grey scale too) wasn't. There was not a single setting that I could even come close to matching the output of my discrete video card.

0-225 or whatever they call it in the Intel control panel looked great but it never would stick. If I right clicked the mouse it would go back to limited or 16-235.

I messed with this for hours and finally decided to put my gt430 back in. The people look like they suffer from rigor mortis and the best I can describe it.

It would be funny but wasting time trying to calibrate the PC to a perfectly calibrated (grey scale too) wasn't. There was not a single setting that I could even come close to matching the output of my discrete video card.

0-225 or whatever they call it in the Intel control panel looked great but it never would stick. If I right clicked the mouse it would go back to limited or 16-235.

There's been some discussion about this recently. I think it takes a registry hack to make it stick.

Two things-1. There is a recent update to the HD 4000 software so you might check to see if you have the most recent version and 2. There is another recent thread which ends up recommending using a Radeon 7770 graphics board. I just installed a Sapphire Radeon Vapor X OC1 1GB GDDR 5 graphics board to solve cadence problems with playing DVDs. HD 4000 got some good press when first released, but graphic board have a habit of leap frogging each other. I was trying to create a system that did not need a graphics board. However, I expected one day I would need to add a graphics board. That day came sooner than I expected.